Ascidian BioCell Group

History and location of the team.

The team was created in 2003 and is part of the “Laboratoire de Biologie de Villefranche sur Mer” set in the “Observatoire Océanologique de Villefranche sur Mer” on the Cote d’Azur in France. We initially began studying egg activation at the moment of fertilization and the meiotic cell cycle in ascidian eggs. We have progressively widened our analysis to include cell division in the ascidian embryo in order to understand how embryonic shape is generated. A new activity of the team is to exploit the usefulness of Phallusia mammillata for marine toxicity monitoring.

Research themes

The main theme of our team is to understand how biomolecular mechanisms lead to the emergence of organismal shape. We use primarily ascidian embryos because they develop with a small cell number (64-cell blastula) and display an invariant cleavage pattern, making them favorable for studying how cell division is involved in shaping the early embryo. In particular, over the past 20 years we have developed the European ascidian Phallusia mammillata for live cell imaging because Phallusia has transparent eggs and embryos which express GFP type constructs at high levels. Using Phallusia we are examining in ever more detail the cellular mechanisms which control the size, positionandnumberof cells during early ascidian development. Finally, we also study the adaptations the cell cycle has made to accomplish maternal meiosis and more recently, we aim at developing the ascidian model for marine toxicity monitoring.